题目内容
一对标准直齿圆柱齿轮啮合，中心距变大时，会出现（）
查看答案
搜索结果不匹配？点我反馈
更多问题
60钢正火时的温度大致为（）
金属材料在外载荷的作用下抵抗塑性变形和断裂的能力称（）
（C）Life will probably be very different in 2050. First of all, it seems that TV channels will have disappeared by 2050. Instead, people will choose a program from a “menu” and a computer will send the program directly to the television. Today, we can use the World Wide Web to read newspaper stories and see pictures on a computer thousands of kilometers away. By 2050, music, films, programs, newspapers and books will come to us in this way.In many places, agriculture (农业) is developing quickly and people are growing fruit and vegetables for export (出口). This uses a lot of water. Therefore, there could be serious shortages. Some scientists infer that water could be the cause of war if we don’t act now.In future, cars will run on new, clean fuels and they will go very fast. Cars will have computers to control the speed of them and there won’t be any accidents. Today, many cars have computers that tell drivers exactly where they are. By 2050, the computer will control the car and drive it to your destination. Space planes will take people around the world in 4 hours. Today, the United States Space Plane can go into space and land on Earth again. By 2050, space planes will fly people from Los Angeles to Tokyo in just two hours.Some big companies now prefer to use robots that do not ask for pay rises or go on strike, and work 24 hours a day. By 2050, we will see robots everywhere — in factories, schools, offices, hospitals, shops and homes.Nowadays, Scientists have discovered how to control genes (基因). Scientists have already produced clones (克隆) of animals. By 2050, scientists will be able to produce clones of people, and decide how they look, how they behave and how much intelligence they have. Scientists will be able to do these things, but should they? By 2050, people will get information mainly by （） .
回火温度的确定，主要以工件的（）值为依据，往往其数值越高，回火温度（）
微信支付 
支付宝支付